"The brain is not porridge"
The brain is highly differentiated and structured. Not one bit is like any other. At the same time, no bit acts alone: each region is highly integrated and connected with other areas.
In fact, the contribution of a brain region to cognition and behaviour is shaped by the input this area receives and the influence it has on others. As such, the unique computational processes of a given area are shaped by its unique constellation of connections.
As such, to better understand our brain it is not helpful to think about individual brain regions. Instead we need to take a systems-level perspective. An understanding of our brain and behaviour necessitates an understanding of neural circuits.
To measure anatomical and functional connectivity we use whole-brain imaging techniques, such as diffusion and functional magnetic resonance imaging (MRI), and electro- and magneto-encephalography (EEG/MEG). Importantly, using MRI techniques we can measure connectivity in both monkey and man, allowing a direct comparison across species using the same technique.
We use these connectivity measure to study brain function from a dynamic perspective but also to map its anatomical organisation.